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https://issues.apache.org/jira/browse/JENA-848?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Andy Seaborne closed JENA-848.
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Close resolved issue on release of Jena 2.13.0.
> jena-text Lucene concurrency issues
> -----------------------------------
>
> Key: JENA-848
> URL: https://issues.apache.org/jira/browse/JENA-848
> Project: Apache Jena
> Issue Type: Bug
> Components: Text
> Reporter: Stephen Allen
> Assignee: Stephen Allen
>
> When using jena-text with an in-process Lucene index, there are concurrency
> issues when multiple requests are accessing the Dataset in using transactions.
> It appears the problem is that a new Lucene IndexWriter is created at every
> transaction start with no concurrency control. Instead the solution should
> be to create a single IndexWriter when the DatasetGraphText is created and
> use that for all requests. This works because the Lucene IndexWriter is
> thread safe and designed for concurrent access.
> This should also increase performance by not continually opening and closing
> the IndexWriter. Also we can use Near Real-Time (NRT) IndexReaders that
> don't have to wait until changes are pushed to disk.
> If concurrent access is not controlled then you can end up with IndexWriter
> objects being closed while they are still in use by other threads:
> {code}
> org.apache.lucene.store.AlreadyClosedException: this IndexWriter is closed
> at
> org.apache.lucene.index.IndexWriter.ensureOpen(IndexWriter.java:645)
> at
> org.apache.lucene.index.IndexWriter.commitInternal(IndexWriter.java:2974)
> at org.apache.lucene.index.IndexWriter.commit(IndexWriter.java:2954)
> at
> org.apache.jena.query.text.TextIndexLucene.finishIndexing(TextIndexLucene.java:122)
> at
> org.apache.jena.query.text.TextDocProducerTriples.finish(TextDocProducerTriples.java:46)
> at
> org.apache.jena.query.text.DatasetGraphText.commit(DatasetGraphText.java:122)
> at
> org.apache.jena.query.text.TestLuceneWithMultipleThreads$2.run(TestLuceneWithMultipleThreads.java:156)
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
> at java.util.concurrent.FutureTask.run(FutureTask.java:266)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> at java.lang.Thread.run(Thread.java:744)
> {code}
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